public with sharing class AccMulti {
    public Account acc {get; set;}
    
    public AccMulti() {
        acc = new Account();
    }
    
    public void populateDescription() {
        String[] values = acc.multi__c.split(';');
        String description = '';
        for(String s : values) {
            description += s += ' ';
        }
      acc.description = description;
    }
    
    
    
    
    
    
    
}